Manufacture of electric mercury bulb switches



Oct-11; 1932.

K. HUNCIKER 1,882,613

MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHES I Filed Sept. 18, 1929 3Sheets-Sheet l INVENTOR KARL HUNCMER X3 ATTORNEY Oct. 11, 1932. KHUNCIKER MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHES Filed Sept. 18,1929 3 Sheets-Sheet 2,

INVENTOR KARL HUNCMEK TTORNEY Oct. 11, 1932. K. HUNCIKER MANUFACTURE OFELECTRIC MERCURY BULB SWITCHES 3 Sheets-Sheet; 5

Filed Sept. 18, 1929 INVENTOR KARL HUNCIKER BY 6 ATTORNEY 1 PatentedOct. 11, 1932 UNITED STATES PATENT OFFICE KARL HUNCIKER, OF CHICAGO,ILLINOIS, ASSIGNORHSO IRA E. MCCABE, OF

' CHICAGO, ILLINOIS MANUFACTURE OF ELECTRIC MERCURY BULB SWITCHESApplication filed September 18, 1929. Serial No. 393,389.

This invention relates to improvements in the manufacture of electricmercury bulb switches and more particularly to the method and automaticapparatus for producing the mercury bulb switches in which theelectrodes and a filling stem are inserted in the open end of a glassbulb, the sides brought together to seal the electrodes and filling stemand support the electrodes in proper positions in one operation, wherebythe bulb switch is prepared for the'insertion of the mercury or otherelectrical conducting fluid, the exhausting of the air, and substitutionof the gas to reduce arcing are accomplished 5 through the filling stemwhich is then tipped off.

It is an object of this invention to provide an automatic apparatuswhich through successive steps produces the bulb switch ready for thereception of the conducting fluid and gas in a prompt and uniform mannerand in addition thereto shapes the bulb adjacent the sealed end, at thesame time, to insurethat the electrodes projecting into the interior ofthe bulb are not contacted by the wall of the bulb.

While it is old in the manufacture of electric light bulbs to producepinch seals and provide filling stems, the accuracy in locating theelectrodes is not so vital as in mercury tube or bulb switches and,while the filling stem is ordinarily, in this art mentioned, provided atthe end opposite the seal, the stem has not been employed for shapingthe bulb before and after the sealing process. The method and apparatusdisclosed herein produces a uniform product automatically at much lessexpense than heretofore, inasmuch as the machine accomplishes the resultwithout manual operation thereby avoiding the variations naturallyresulting between the products of individual manual operators.

With these and other objects in view, reference is made to theaccompanying sheets of drawings which illustrate preferred forms of thisinvention, with the understanding that minor detail changes may be madewith out departing from the scope thereof.

In the drawings:

Figure l is a fragmentary top plan view illustrating the essentialelements of the apparatus to carry out the steps of this invention.

Figure 2 is a fragmentary plan View of the end of a filling stem.

Figures 3 and 4; are detail plan views of the respective leading inwires and electrodes employed in one type bulb switch.

Figure 5 is a detail plan view of the open ended bulb before it issealed.

Figures 6 and 7 are views in end and side elevations, respectively of asealed bulb switch of the type employing the leading in wires andelectrodes illustrated in Figures 3 and 4.

Figures 8 and 9 are similar views of another type of bulb switchemploying a pair of leading in wires and electrodes similar to Figure 3and a modified form of electrode secured to a pair of leading in wires;

Figure 10 is an enlarged detail view in side elevation, with partsbroken away, of a work holder supporting an open end bulb, electrodesand filling stem with the compressing jaws open before the opened end ofthe bulb is sealed. 7

Figure 11 is a View similar to Figure 10 showing the jaws completing theseal and the air block and inclined track as supported below the table.

Figure 12 is a View similar to Figure 11 with the jaws opened aftercompleting the seal ofthe open end of the bulb showing the second airblock as supported below the table.

Figure 13 is an enlarged fragmentary View partly in central verticalsection and partly in side elevation of the filling stem core rod andreciprocating means therefor.

Figure 14 is a fragmentary view'in side elevation showing thearrangement of 'aws to-form the type bulb switch shown in ig-' ures 8and 9,

The apparatus for carrying out this invention, as illustrated upon thedrawings, includes a rotatable table or turret 1, preferably circular inshape, having a plurality of equally spaced upwardly extending workholder bosses 2 also arranged equi-distant from the center of rotation.This table or turret 1 is provided with a step byfistep rotatingmechanism of which there are several types upon the market and as thismechanism is not a part of this invention it is not necessary toillustrate or further describe such a well known mechanism.

' Each boss 2' is provided with a central vertical bore for rotatablymounting a vertical work support referred to in its entirety by thereference numeral 3 upon Figure 1 pf the drawings. The work holders 3are brought at preferably four successive stops of the table or turret 1between the horizontal flames of oppositely disposed gas jets 4 whichare supported in the same plane above the top of the rotatable support 1in any desired manner and connected to a source of gas supply. Gas jetsof this character-being well known in the glass manipulation art it isthought they need no further illustration nor description only to statethat, as shown, upon rotation of the table 1 in the direction of thearrow, the flames of the first three jets are increased successively inintensity and the fourth diminished preferably belowthe intensity of thefirst jet in the series.

This apparatus is designed to produce mercury bulb electric switches ofthe type shown in Figures 2 to 9, inclusive. Each bulb switch, as shownin Figures 2, 3, 4-and 5, includes a hollow glass tube 5 which forms afilling stem, to be hereinafter described; a leading in wire 6 welded toan electrode 7 which is bent near its extremity at right angles to itsmain body and which is preferably sheathed within a short glass .tube 8,

as shown; a leading in wire 9 welded to a forked electrode 10 whichembraces and supports a cup 11 of insulating material at an angle to themain body with the tines of the fork extending therebeyond preferably inthe same plane as the leading in wire 9'; and an open ended tubularglass bulb 12. In the form shown in Figures 6 and 7 the side walls ofthe open end of the tubular glass bulb 12 have been brought together tocentrally embrace the filling stem 5 with its open end com municatingwith the interior of the bulb, with the leading inwires 6 and 9 onopposite sides thereof with the glass sheath 8 imbedded in the closuresupporting the angular terminal of the electrode 7 entering the interiorof the cup 11 which is supported by the forked electrode 10 from theleading in wire 9 to incline in the direction of the bottom of, theopposite closed end of the bulb 12 with the tines of the electrode 10extending parallel to but separated from the side walls of the bulb.Figures 8 and 9 illustrate another form of this bulb switch in which theleading in wires are arranged in pairs, one

f pair being similar to leading in wire 6' having the bent electrode 7within the sheath 8, as above described, and the other pair similar tothe leading in wire 9 except the electrode instead of bein forked is acontinuous loop 13 joined at eac end to the leading in wires.

the respective bulb 12. After being so produced by this improvedapparatus, the assembly is removed and the switch is completedbyexhausting the 'air through stem 5 from the interior of the bulb 12and replacing it by filling the bulb through the stem with the requiredamount of mercury and inert gas and then tipping off or sealing thefilling stem 5 adjacent the closed end of the bulb 12.

This invention not only contemplates supportingthe filling stem 5 withthe leading in wires 6 and 9 in the relation shown in Figures 7 and 9,and sealing them in that position within the sealed end of the bulb 12by heating that end to plasticity and compressing it, but also to employthe filling stem 5 to admit air under sufficient pressure just beforethe compressing operation is completed and immediately thereafter whilethe compressed end is cooling to maintain the tubular contour of theheated walls immediately adjacent the seal and prevent such heated andsemiplastic walls from collapsing, elongating or tapering from thetubular cold portion to the sealed end in order that in the resultantproduct the electrodes 7 and 10 or 13 with the cup 11 will all be heldin the proper places free and out of contact with the side walls of thebulb 12.

An apparatus of this general type has been constructed by Ira E. McCabeand myself as disclosed in our joint application, Serial No. 366,916,filed -May 29, 1929, so that this invention applies to the particularmanner and times as well as the mechanical construction for admittingthe air under pressure to the interior of the heated and cooling bulb12.

The general construction and operation of the apparatus is as follows.Each boss 2 upon the step by step revolving table 1 supports a workholder 3. Each work holder includes a shouldered base 14 having acentrally depending tubular guide 15 adapted to pass through thevertical bore of the boss 2 and mount below the table 1 a pulley or gearwheel 15'" to cooperate with the rotating mechanism of the table torotate the work holder continuously at each stop of the table during itsstep by step rotation movement as each work holder halts successivelybetween each successive pairs of gas jets. Since such mechanism is wellknown in glass manipulating machinery it is not further dis- .closed nordescribed herein as it forms no part of this particular invention. It ispreferable to provide ball bearings 17 between the top of the boss 2 andunder side of the. shoulder of the base 14.

An electrode and filling stem positioning block 16 is supported in axialalignment with the base guide 15, upon a cross head 17 adj ustablymounted upon supports 18 extending upward from opposite sides of thecenter of the base 14. The supports 18 mount above the cross head 17, areleasable bulb clamping and positioning device including a rectangularframe 19 pivoted at its corners, the longer sides provided with centralinwardly extending coacting bulb clamping members 20 with the shortersides centrally pivoted upon the upper extremities of the supports 18.One support is hollow and the pivot upon that support is in the form ofa shaft 21 secured at its upper end to one of the shorter members of theclamping and positioning frame 19 and passes through the support andprojects below the base 14 and mounts a wing nut 22 held thereonpreferably by a set screw, as shown. A resilient member 23 is secured tothe base 14 having its free outer end indented and adapted to engage theouter edge of one of the wings of the nut 22 with the indented member 20in the position assumed when holding a bulb 12 between them. 'A coilspring 24 secured at one end to the outer end of the outerwing of thenut 22 with the other end engaging the base 14 and exerts sufficienttension against resilient member 23 so that when it is desired to removethe bulb 12 the wing is manually released and the spring 24 causestheframe 19. to open and hold it open until another bulb-is inserted andthe members 20 caused to engage it by manually rotating the nut 22 untilthe wing engages the indentation in the resilient holding member 23.

The electrode and filling stem positioning block 16 is removable, isprovided with a central bore for positioning a filling stem 5, as

shown, and upon the top with oppositely disposed recesses for receivingand positioning the electrode supporting leading in wires.6 and 9 with apositioning pin 25 extending from one side adapted to engage in a notchin the cross head 17 to maintain its position. Before operating theapparatus a plurality of equal length filling stems 5 are placed withinreach of the operator also a plurality of blocks 16 which have beenfilled with the proper electrode supported leading in wires. In startingthe operation a filled block 16 is placed upon the cross head 17 and afilling stem 5 inserted within the central base. Another adjustablecross head 26 is mounted upon the supports 18 a sufficient distancebelow cross head 17 to engage the lower end of the filling stem 5 andsupport it with its upper end the proper distance above the top of theblock 16. Then the bulb clamp 20 on the frame 19 of the bulb positioningdevice is opened by rotating the wing nut 22 and the open end of a bulb12 is placed over the electrodes and filling stem projecting above thetop of the block 16 and the wing nut 22 rotated to clamp the bulb 12 andby means of being brought with engagement with the member 23 will holdthe bulb in that position until manually released and removed. Themechanism of the apparatus is started and as each empty work holderhalts in the step by step rotation of the table 1 it will be supplied bythe operator with a filled block 16, filling stem 5 and bulb 12. As thetable halts at each step the work holder is continuously rotated. Whenthe work holder halts between the flames of the first pair of gas jets4, the flames play upon opposite sides of the open end of the bulb 12and as the work holder continuously rotates the lower walls of the bulbare gradually heated, then the work holder is advanced and haltedbetween the more intense flames of the second pair of jets, rotatedtherebetween, and further heated and to a higher degree, then the workholder is advanced and halted between the still more intense flames ofthe third pair of gas jets, rotated therebetween. At this point thecontinued application of heat in increasing degrees has brought thelower portion of the walls of the open end of the bulb to a uniformstate of plasticity sufficient to be compressed and united to embraceand seal the electrode supporting leading in wires 6 and 9 and the endof the filling stem 5.

The compressing and sealing the open end of the bulb to embrace andsupport the leading in wires and filling stem is accomplished by a pairof oppositely disposed compressing jaws 27 pivotally mounted withinrecesses provided therefor in the cross head 17. The jaws are movedabout their pivots by links 28 pivoted at one end to the respective jawsand at the other to oppositely disposed ears 29 upon a tubular actuatingmember 30 which is mounted to reciprocate axially within the base 14,tubular guide 15 within the boss 2, and to normally extend below thetable 1 when the jaws 27 are in open position, as shown in Figures 10and 12. As the work holder is moved from between the flames of greatestintensity with the open end 0f the bulb in a compressible state, thelower end of the actuating member 30 projecting below the rotating table1, is caused to engage and ride over an inclined track 31, as shown inFigure ll, whereby the jaws are brought together to engage the oppositesides of the open end of the bulb to compress them and then released toassume the normal open po sition.

At the halt following the compression and sealing of the bulb the workholder is rotated between the less intense flames of the fourth pair ofjets, to prevent too rapid cooling, and

ICC

' to form the type of bulb switch shown in Figures 6 and 7. When it isdesired to form the type shown in Figures 8 and 9, two pairs ofoppositely disposed jaws are provided of the form shown in Figure 14with the additional jaws 32 pivotally mounted upon the exterion of thecross head 17 and connected by similar links 28 to the actuating memberThe leading in wires 6 and welded electrodes 7 with sheath 8 arearticles of standard mass production as well as leading in wires 9 andwelded electrodes 10 embracing and supporting cup 11 and likewiseleading in wires 9 and welded electrode 13 embracing and supporting cup11, so that they are all of the same dimensions and similar inconstruction and when placed in block 16 each set will be similarlysupported to the preceding set. The cross head 17 is adjusted so thatwhen the open ended bulbs 12 of different sizes and lengths are engagedby the position frame 19 the electrodes will project into the interiorof the bulb the proper distance to be embraced and sealed within thecompressed walls of the open end. The filling stems 5 are preferably ofuniform length for bulbs of the same size but may be of various lengthsfor various size bulbs and the cross head 26 is therefore adjustable sothat the stem may be always supported with its upper end the properdistance above the block 16.

To prevent the heat and pressure during the compressing action of thejaws upon the heated and semi-plastic walls of the open end of the tubeclosing the opening through the filling stem, a core 33 is provided inthe form of a rod of less diameter than that of the filling'stem and isadjustably mounted upon a reciprocating member 34 mounted to slide on aguide 35 carried upon the cross head 26 and within the actuating member30. The core rod 33 passes through an aperture provided therefor in thecross head 26 and through the filling stem bore in the block 16 and isnormally adjusted by the set screw 36 base 14 by a coil spring 39 whichnormally draws the free end downward in the direction of the base. Theoperating lever 37 is connected to the reciprocating member 34 by apivoted link 40. On the outer surface of the lever 37 a flat spring 41is secured at one end and two pins 42 and 43 secured adjacent the freeend which pass through apertures therefor in the lever 37. The pin 42 ispositioned to normally enter a vertical groove in a detaching block 44carried on the adjacent jaw operating link 28 and the pin 43 is arrangedto be adapted to engage within a horizontal groove 45 upon the adjacentsupport 18 and hold the free end of the lever in its uppermost position,when manually lifted, against the tension of the spring 39 when the jaws27 are open and thereby support the core end in proper relation to thetop of the block 16 through the link 40 and reciprocating member 34, asshown in Figure 10. The groove in the detaching block 44 is curved atits lower end to join the outer surface of the block and the block is sopositioned upon the link 28 that with the lever held by the pin 43 inits upper position as the link 28 moves upward to close the jaws 27, asshown in F igure 11, the curved lower end of the groove forces the pin42 outward so that at the end of the closing movement of the jaw thespring 41 withdraws the pin 43 from the groove 45 and releases the lever37 to be drawn downward by the spring 39 and withdraw the core rod 33from within the sealed end of the bulb 12, as shown in Figure 12. Thecore rod 33 remains in this position until the operator removes thesealed bulb 12 and replaces the empty block with one supporting anotherset of electrodes and inserts another filling stem. The sealed bulb 12is manually Gil released by one hand of the operator releasing thewingnut 22 and the same hand may be used to thereafter lift the free end ofthe v lever 37 until the pin 43 enters the groove 45 while the otherhand is employed in removing the sealed bulb embracing the leading inwires and filling stem.

As the open end of the bulb 12 is rotated between the flames of thefirst two sets of gas jets its temperature is increased graduallywithout fracture to suchextent that as it rotates between the flames ofgreatest intensity of the third set of gas jets it becomes sufficientlyplastic on leaving this position to be compressed to seal thereinthe-leading in wires 6 and 9 and filling stem 5. While in thissemi-plastic or plastic state the weight of the heated glass of the openend will tend to cause the lower walls to approach each other or taperdownwardly toward the center and after the sealing action of the jaws2'7 and while rotating between the flames of lesser intensity of thefourth set of gas jets this tendency to taper is increased by the weightof the compressed sealed end. To prolong the active life of the bulbswitch in use and to prevent cracking, the electrodes as well as thecontained cup 11 should be entirely free of the sides of the bulb, andto so maintain them the cylindrical contour of the bulb should bemaintained adjacent the sealed end, so that it is importantto preventthe tapering of the side walls when in a semiplastic or plasticcondition.

To accomplish this result, this invention contemplates the admission ofair under sufficient pressure into the interior of the bulb justpreceding the sealing action of the jaws 27 and during the halt of thesealed' bulb between the last set of gas flames. To this end, thereciprocating actuating member 30 is tubular in form as well as thereciprocating member 34 and guide 35 and that portion of the member 34which is thickened to adjustably engage the lower end of the core rod 33is perforated so that there is an air passage from the bottom of theactuating member 30 through the aperture in the cross head 26 and, asthe core rod is of less diameter than that of the filling stem 5, alsothrough the filling stem. As the work holder assumes its positionbetween the flames of greatest intensity and is halted the open lowerend of the actuating member 30 wipes over and registers with astationary block 45 which contains a duct 46 connected to a source ofair under the desired pressure, not shown, and is provided with a port47 adapted to register with the halted open end of the actuating member30, whereby air under suflicient pressure is admitted into the interiorof the bulb 12 during this heatin period through the upper end of thefilling stem, as shown in full lines in Figures 10 and 12 and indicatedin dot and dash lines in Figure 11, to maintain the cylindrical form ofthe open end of the bulb 12. As the work holder advances to the positionbetween the last set of gas flames the jaws 27 complete the seal asshown in Figure 11 and then open as shown in Figure 12.

As the core rodlreoiprocating lever 37 is released immediately the openend is sealed, the core 33 is withdrawn from the retracted end of thefilling stem 5 within the sealed end, as shown in Figure 12, tl1e travelof the core rod 33 is so adjusted that when in this position there is anunobstructed passage from the lower part of the filling stem into theinterior of the sealed bulb. As the work holder halts between the lastset of gas flames the lower end of the tubular actuating member 30 wipesover a stationary block 48 similar to the block 45, having a duct 49also connected at one end to a source of air under sufficient pressureto pass through a port 50 registering with the open end of the haltedactuating member 30 and through said member and through member 34, guide35, cross head 26 and filling stem 5 and to prevent the walls of thebulb adjacent the sealed end from excessive tapering and maintain thecylindrical form as near to the seal as possible.

This invention provides several improveopen end of the bulb issuccessively rotated between flames of increasing intensity, and duringthe halt of the table and the rotation of the work-holder between theflames of greatest intensity, just before the lower walls of the bulbare, compressed, the heat is so intense that the walls of the bulbbecome white hot and would, under normal conditions, transmit such heatto the end of the filling stem which projects into the bulb and causethe filling stem to become semi-plastic,

possibly to become deformed, so that, when the jaws compress the walls,the contact of the walls with the semi-plastic filling stem will sealthe core rod to the filling stem. To prevent such an occurrence, airunder pressure is caused to pass continually through the filling steminto the surrounding open ended bulb which not only cools the interiorof the filling stem but also, in passing into the ,bulb and then out theopen end, envelops the exterior of the filling stem and sets up acurrent of air which carries the intense heat of the walls of the bulbaway from the g stem, so that after the operation of the jaws halt inthe step by step rotation of the table.

In order to admit air through the filli'ng stem at the halts on eachside of the compressing operation, each member of the core rod actuatingand supporting members is tubular in form and the actuating member ismounted to extend below the table to register during these halts withair ports from which air under pressure will pass through said membersand supported filling stem about the core rod.

What I claim is: a

1. The method of automatically producing electric liquid contact bulbswitches by ma- ,chinery including a step by step movement in which thefirst step consists in locating and positioning electrodes with afilling stem containinga removable solid core interposed between theelectrodes and positioning and supporting the open end of a bulbthereabout,

.then through the next succeeding steps pass the open end of the bulbbetween gas flames playing on oppositely disposed walls thereof and whensufliciently plastic compress the plastic walls about the containedelectrodes and filling stem to embed the same and form a sealed closurefor the bulb with the electrodes extending within the interior, pass airthrough the filling stem to prevent its adhering to its core before thecompression of the plastic walls, and remove the filling stem core toprovide an opening into the interior of the sealed bulb, admit air underpressure to the interior of the bulb to maintain its contour and in thenext succeeding steps reduce the temperature of the seal, and lastlyremove the completed structure from the machine.

2. The method of automatically producing electric liquid contact bulbswitches by machinery including a step by step movement in which thefirst step consists in locating and positioning electrodes with afilling stem containing a removable solid core interposed between theelectrodes and positioning and supporting the open end of a bulbthereabout, then through the next succeeding steps pass the open end ofthe bulb between gas flames playing on oppositely disposed walls thereofand when sufiiciently plastic compress between molds the. plastic wallsabout'the contained electrodes and filling stem to embed the same andform a sealed closure for the bulb with the electrodes extending withinthe interior, pass air through the filling stem to prevent its adheringto its core before the compression of the plastic walls, and remove thefilling stem core to provide an opening into the interior of the sealedbulb, admit air under pressure to the interior of the bulb to mold theplastic wall above the closure, and in the next succeeding steps reducethe temperature of the seal, and lastly remove the completed structurefrom the machine.

3. The method of producing electric bulb mercury switches which includespositioning of the open end of the bulb about the electrodes andafilling stem containing a removable solid core supporting thereunder,applying heat to the open end of the bulb until it becomes plastic,passing air through the filling stem during the heating of the wall ofthe bulb to prevent heat therefrom causing the filling stem adhering tothe core therein, compressing the plastic wall to embrace, embed andseal the electrodes and filling stem therein and form a sealed closure,and thereafter removing the core while the bulb is still plastic andblowing through the sealing stem and thereby shaping the bulb.

KARL 'HUNCIKER.

